Re: olive leaf extract anticancer

 Perhaps this is a very stupid question, but if cancer is caused by viruses, is it contageous... like a flu or cold?

Technically yes.  Cancer viruses are transmissible.  For example, HPV viruses can be spread by contact or sexua| intercourse.  Hepatitis viruses can be spread through several means as well.  And the HIV virus is believed to be spread through various means including mosquito and bedbugs, which have been shown to carry the virus.  HIV is actually a leukemia/lymphoma virus, which is interesting since the first leukemia virus, from chickens, was found to be airborne transmitted.  But transmission does not mean chronic infection, nor the production of cancer.  These require sufficiently suppressed immune systems to allow the viruses to take hold and cause problems such as cancer.  Same principle as how you can be around someone with a cold or flu and not develop that cold or flu yourself.  Viruses require immune suppression to take hold in a person's body.

Can you explain a bit what a "cancer virus" is, and how they are formed in us? Thank you!

In short, viruses are genetic material (RNA or DNA) encapsulated by a protein or lipid (fatty) coating.  Viruses cannot replicate though without a host cell.   Once inside the cell viruses can use the cell to set up a "factory" with the cell's genes to produce copies of itself.

Cancer viruses are simply viruses that can cause cancer.  Once they insert their genetic material in to the genetic material of another cell they can create mutations that lead to the formation of cancer.